2015-11-29

This cheap ($0.99 - $1.19) infrared remote control kit from ebay contains small plastic remote controller, VS1838B infrared receiver with mini board from it and piece of cable for prototyping.

Remote controller gives feels very weird. It's very light - you almost can't feel its weight. Buttons are spongy and some of them (mostly first column) are not giving too much feedback.

According to description on the back CR2025 should be used. Fortunately more popular CR2032 (3.2 mm instead of 2.5 mm height) fits fine.

VS1838B seems to be equivalent of TSOP1338. Operating voltage range si 2.7V - 5.5.V. "38" stands for carrier frequency this receiver is intended to. If you are planning to use this kind of IR receiver in other kind of application than remote control be aware that IR signal has to be modulated to be received (not cut off by internal receiver filters).
Remote is using NEC protocol, here is captured trace from sensor output:

2015-11-02

This cheap (starting at $1.08 incl. shipping on ebay) USB sound card can be easily modified to capture DC voltage:

To bypass AC coupling remove C6 (if not removed it would act as a low-pass filter later) and connect 120k resistor to its pad - this would be oscilloscope/recorder input. This would result in 0-6V measurements range.

Some other cheap sound cards can't capture DC with similar modification, perhaps because of digital filtering, but this model is worth a try if you don't mind its drawbacks - single channel only (you won't find better at this price) and some DC voltage present on input (2V with 250k source resistance) that may disturb measurements. I won't replace your bench scope but may be handy with low-speed (by the rule of thumb useful measured frequency range is 0-4kHz) signal recording.